I want to have a snake block the hero’s path until he gets a weapon, and then once he has it, move out of the way. As far as I can see, character sprites are the only ones that can move. I could replace the snake with something from the sprite sheet, but that’s not exactly preferable.

You could put an invisible actor over the snake, put in a token called “sword” or something, and a door right behind the snake. Once the character has the sword, they are teleported to a door right behind the snake. I know the snake doesn’t move, but that’s all I can think of. Good luck!